What do you want to know?

In his book God at the Edge, Rabbi Niles Goldstein journeys into the dark places, frightened but confident that he will come out of it feeling better or at least wiser.

"I've still got a lot to learn," he admits. "I'm not railing against death as I used to," largely because his experiences have taught him that he has no choice. "I still want to live, of course, though not forever. I've gone from resignation to acceptance, but I want to move even farther beyond that: to celebrate the reality of my finitude. That's true spirituality."

Here are 4 people who lived on the edge and found God there:

St. John of the Cross: imprisoned by fellow monks in 1577, he spent months being tortured and starved while composing and memorizing great spiritual poetry.

Julian of Norwich: a medieval anchoress who lived isolated from the world, sealed alone in a cell; her account of godly visions was the first volume written by a woman in English.

Rabbi Nachman of Bratslav: Born in 1772, this Ukrainian Hasidic master embarked on a lifelong pilgrimage, a voluntary state of exile as ameans of self-purification.

Soren Kierkegaard: the 19th-century Danish philosopher became a pariah for his attacks on mainstream Christianity and his belief that God is truly elusive and untouchable.